Toxicology (main): Difference between revisions

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==Exam==
==Background==
===Epidemiology===
*In 2014, ~2.2million human exposures reported to US poison control centers
*Top 5 substance classes:
**analgesics (11%)
**cosmetics/personal care products (8%)
**household cleaning substances (8%)
**sedatives/hypnotics/antipsychotics (6%)
**antidepressants (4%)
*1,835 human exposures resulted in death


{{Autonomic nervous system receptors}}


- All VS (Temp, RR,HR, BP)
==Clinical Features==
{{Template:Toxidrome Chart}}


- Neuro Exam
==Differential Diagnosis for Specific Signs==
===[[Hyperthermia]]===
*Altered Metabolism
**[[Aspirin (Salicylate) Toxicity]]
**Withdrawal states (e.g. [[baclofen withdrawal]]
**[[Thyroid]] hormones
**[[Dinitrophenol]]s
*Increased Muscle Activity
**Withdrawal, [[sympathomimetics]]
**[[MAOI Toxicity]]
**[[PCP]], [[LSD]]
**[[Lithium]]
**[[Serotonin Syndrome]]
*Impaired Heat Dissipation
**[[Anticholinergics]]
**[[Antihistamines]]
**[[Antipsychotics]], TCAs
**[[Phenothiazines]], [[Lithium]], LevoDopa
*[[Malignant Hyperthermia]]
**Anesthetics
*[[Neuroleptic Malignant Syndrome]]


    Level of consciousness
===[[Hypothermia]]===
*Exposure
**[[Ethanol Toxicity]]
**[[Sedative/Hypnotics]]
**[[Opioids]]
**[[TCAs]]
**[[Phenothiazines]]
**[[Insulin]] ([[Hypoglycemia]])
**[[Carbon monoxide]]


    Pupillary exam
===Increased Respiratory Rate===
*Direct stimulation
**[[Aspirin (Salicylate) Toxicity]]
**[[Metabolic Acidosis]]
**[[Dinitrophenol]], pentachlorophenol
**[[Hepatic failure|hepatic]]/[[renal failure]]
**CNS stimulants ([[cocaine]], [[amphetamine]], [[theophylline]])
*Tissue [[Hypoxia]]
**[[CO]]
**[[Cyanide]]
**[[Hydrogen Sulfide]]
**[[Methemoglobinemia]]


    Motor response
===[[Respiratory failure|Respiratory Depression]]===
*Central Depression
**[[Antipsychotics]]
**Chlorinated [[hydrocarbons]]
**[[Sedative/Hypnotics]] ([[Ethanol Toxicity]], glycols)
**[[Tricyclic (TCA) Toxicity]]
**[[Lomotil toxicity]]
**[[Opioids]]
**[[Marijuana]]
*Muscle Failure
**[[Organophosphates]]
**[[Marine Toxins]]
**[[Nicotine Poisoning|Nicotine]]
**[[Strychnine]]
**[[Botulism]]
**Mojave [[rattlesnake]], Cobra


- Skin Exam - moisture, temp
===[[Bradycardia]]===
PACED
*[[Propranolol]]/[[beta-blockers]], poppies ([[opiates]]), propoxyphene,
[[physostigmine]]
*[[Acetylcholinesterase inhibitors|Anticholinesterases]], [[antiarrhythmics]]
*[[Clonidine]], [[calcium channel blockers]]
*[[Ethanol]] or other [[toxic alcohols|alcohols]]
*[[Digoxin]], [[digitalis]]


- Lung Exam
===[[Tachycardia]]===
FAST
*Free base or other forms of [[cocaine]]
*[[Anticholinergics]], [[antihistamines]], [[antipsychotics]], [[amphetamines]], [[alcohol withdrawal]]
*[[Sympathomimetics]] (cocaine, caffeine, amphetamines, PCP), solvent abuse, strychnine
*[[Theophylline]], [[TCA]], [[thyroid]] hormones


- Bowel Sounds
===Hypotension===
CRASH
*[[Clonidine]], [[calcium channel blockers]]
*Rodenticides (with [[arsenic]], [[cyanide]])
*Antidepressants, [[aminophylline]], [[antihypertensives]]
*[[Sedative/Hypnotics]]
*[[Heroin]] or other [[opioids]]


===[[Hypertension]]===
CT SCAN
*[[Cocaine]]
*[[Thyroid]] supplements
*[[Sympathomimetics]]
*[[Caffeine]]
*[[Anticholinergics]], [[amphetamines]]
*[[nicotine toxicity|Nicotine]]


==DDx==
===Miosis===
COPS
*[[Cholinergic]]s, [[clonidine]], [[carbamates]]
*[[Opioids]], [[organophosphates]]
*[[Phenothiazines]], pilocarpine, pontine hemorrhage
*[[Sedative/Hypnotics]]


===Mydriasis===
SAW
*[[Sympathomimetics]]
*[[Anticholinergics]]
*Withdrawal syndromes


I. HYPERTHERMIA
===[[Coma]]===
LETHARGIC
*[[Lead]], [[lithium]]
*[[Ethanol]], [[Ethylene glycol toxicity|ethylene glycol]]
*[[TCA]], [[thallium]], [[toluene]]
*[[Heroin]], hemlock, [[hepatic encephalopathy]], [[heavy metals]], [[hydrogen sulfide]], hypoglycemics
*[[Arsenic]], antidepressants, [[anticonvulsants]], [[antipsychotics]], [[antihistamines]]
*[[Rohypnol]], [[risperidone]]
*[[GHB]]
*[[Isoniazid]], [[insulin]]
*[[Carbon monoxide]], [[cyanide]], [[clonidine]]


1) Altered Metabolism
===[[Seizures]]===
OTIS CAMPBELL
*[[Organophosphates]], oral hypoglycemics (e.g. [[sulfonylurea]])
*[[TCA]], [[theophylline]], [[tramadol]]
*[[Isoniazid]], [[Insulin]]
*[[Sympathomimetics]], [[salicylates]], [[strychnine]]
*[[Camphor toxicity|Camphor]], [[carbon monoxide]], [[cyanide]], chlorinated [[hydrocarbons]], [[cocaine]]
*[[Anticholinergics]] (antihistamines), [[amphetamines]], antidepressants (citalopram, [[Tricyclic antidepressant toxicity|TCAs]], [[bupropion]])
*[[Methanol]], Methylxanthines ([[theophylline]], [[caffeine]]), [[MAOI Toxicity|MAOI]]
*[[PCP]], [[propranolol]]
*[[Benzodiazepine withdrawal]], [[bupropion]], botanicals (hemlock, [[nicotine toxicity|nicotine]]), [[GHB]]
*[[ETOH withdrawal]], [[ethylene glycol]]
*[[Lead]], [[lithium]]
*[[Lidocaine]], [[lindane]] (pesticide, scabies)


- salicylates
===Skin findings===
====Diaphoresis====
SOAP
*[[Sympathomimetics]]
*[[Organophosphates]]
*[[Acetylsalicylic acid]] and other salicylates
*[[Phencyclidine toxicity|PCP]]
====Dry skin====
*[[Antihistamines]], [[anticholinergics]]
====Bullous lesions/blisters====
*[[Barbiturates]]
*[[Mustard agent (vesicants|Mustard gas]]
*[[Snake bites|Snakes]] and [[spider bites|spiders]]
====Flushed/red appearance====
*[[Anticholinergics]]
*[[Niacin]]
*Boric acid
*[[Carbon monoxide]]
*[[Cyanide]]
====Cyanosis====
*[[Benzocaine]] and other local anesthetics
*[[Cyanokit]], nitrites, nitrates, well water (nitrates)
*[[Antimalarials]]
*[[Quinolones]]
*[[Dapsone]] (used to treat leprosy, PCP pneumonia, toxoplasmosis, dermatitis herpetiformis, brown recluse bite)
*Aniline dyes
*Phenazopyridine<ref>Jeffery WH, Zelicoff AP, Hardy WR. Acquired methemoglobinemia and hemolytic anemia after usual doses of phenazopyridine. Drug Intell Clin Pharm. 1982 Feb;16(2):157-9.</ref>
*Nitrates, nitrites
*Ergotamine toxicity|Ergotamine]]
====Acneiform [[rash]]====
*Bromides
*Chlorinated aromatic [[hydrocarbons]]


- withdrawal states
==Evaluation==
===Toxicological Exam===
*All vital signs (Temp, RR, HR, BP) + bedside glucose
*[[Neurologic exam]]
**Level of consciousness
**Pupillary exam
**Motor response
**DTRs
*Skin Exam - moisture, temp, evidence of injection drug abuse
*Lung Exam
*Bowel Sounds
*[[ECG]] (ie. look for [[QT prolongation]], QRS prolongation, etc)
*Consider CBC, BMP, urinalysis (with ẞ-HCG if appropriate), urine toxicology screen, serum alcohol concentration, VBG
**The urine screen is a qualitative test -> positivity ≠ acute toxicity
**It can be falsely positive due to cross-reactivity
**It can be falsely negative if the substance ingested does not cross-react with the tested analyte
**The diagnosis of intoxication is clinical!!!


- thyroid hormones
==Management==
*Depends on agent
*See [[antidotes]]
*"Coma cocktail" when suspecting toxic ingestion (mnemonic = "DONT")
*#[[Dextrose]] (50mg IV)
*#[[Oxygen]]
*#[[Naloxone]] (0.2-0.4mg IV/IM, repeat dose 1-2mg)
*#*Empiric opioid ingestion treatment
*#[[Thiamine]] (50-100mg)
*#*Treat or avoid [[Wernicke encephalopathy]]
*#*Though some suggest giving thiamine prior to dextrose, do NOT let this delay treatment of hypoglycemia!
*#*Case reports of dextrose precipitating Wernicke's involved thiamine-deficient patients receiving prolonged course of IV glucose, NOT with single bolus<ref>Donnino MW, Vega J, Miller J, Walsh M. Myths and misconceptions of Wernicke's encephalopathy: what every emergency physician should know. Ann Emerg Med. 2007;50(6):715-21.</ref><ref>Gussow, L. Myths of Toxicology: Thiamine Before Dextrose. Emergency medicine news. 2007;29(4):3-11.</ref>


- dinitrophenols
==Disposition==
*Depends on agent


==See Also==
*[[Altered mental status]]
*[[Traditional chinese medicine toxicology]]
*[[Drug_levels|Drug Levels]]
*[[Antidote]]
*[[Camphor toxicity]]
*[[In-Training Exam Review]]


2) Increased Muscle Activity
==References==
<references/>


- withdrawal, sympathomimetics
[[Category:Toxicology]]
 
[[Category:EMS]]
- MAOI
 
-PCP, LSD
 
- lithium, amoxapine
 
 
3) Impaired Heat Dissipation
 
- anticholinergics
 
- antihistamines
 
- antipsychotics (TCAs)
 
 
4) Malignant Hyperthermia
 
- anesthestics
 
 
5) Neuroleptic Malignant Syndrome
 
- phenothiazines, Lithium, LevoDopa
 
 
II. HYPOTHERMIA
 
1) Exposure
 
- alcohol, sedative hypnotics
 
- narcotics, TCAs, phenothiazines
 
- Insulin (hypoglycemia)
 
 
III. INCREASED RESPIRATORY RATE
 
1) Direct Stimulation
 
- salicylates
 
- metabolic acidosis
 
- dintirophenol, pentachlorophenol
 
- hepatorenal failure
 
- CNS stimulants (cocaine, amphet,
 
theophylline)
 
 
IV. TISSUE HYPOXIA
 
- CO
 
- cyanide
 
-hydrogen sulfide
 
- methemoglobinemia
 
 
V. RESPIRATORY DEPRESSION
 
1) Central Depression
 
- antipsychotics
 
- chlorinated hydrocarbons
 
- alcohols/glycols, sedative/hyp
 
- TCAs
 
- Lomitil
 
 
2) Muscle Failure
 
- organophosphates
 
- marine toxins
 
- nicotine
 
- strychnine
 
- botulinis
 
- Mojave rattlesnake, Cobra
 
 
VI. AUTONOMIC NERVOUS SYSTEM
 
1) Parasympathetic - ACh is transm
 
a) Muscarinic
 
-receptors in heart, eye, lung, GI, skin and sweat glands
 
- Bradycardia
 
- Miosis
 
- Bronchorrhea / Bronchospasm
 
- Hyperperistalsis (SLUDGE)
 
- Sweating
 
- Vasodilation
 
 
b) Nicotinic
 
- receptors in both sympathetic and parasympathetic nervous systems
 
- fasciculations, flaccid paralysis
 
- tachycardia, hypertension?
 
 
2) Sympathetic
 
ALPHA EFFECTS - vessels, eye, skin
 
- Mydriasis, HTN, Sweating
 
BETA EFFECTS - heart, lungs
 
- Tachycardia, Bronchodilation
 
 
==Toxidromes==
 
 
1. MIXED CHOLINERGIC (ORGANOPH) Temp Normal
 
RR Increased (spasm -M
 
inc secretions)
 
Decreased (N- paralysis)
 
HR Tachycardia (N-pregang
 
or Normal or Brady (M)
 
BP HTN (N)
 
LOC Normal to Lethargic
 
Pupils Miotic (M) or Nl or Mydr (N)
 
Motor Facciculations, Flacid Paral
 
Skin Sweating (mod to marked
 
Lungs Bronchospasm/ rrhea
 
BSs Hyperactive (SLUDGE)
 
 
ANTICHOLINERGIC
 
(TCAs, antihist, phenothiazines)
 
Temp Nl to Inc (dec sweating)
 
RR Nl to Dec
 
HR Tachy (unopposed B1)
 
LOC Nl or delirious, agitated,
 
psychotic, comatose
 
Pupils Mydriasis (unoppos alpha)
 
Motor Nl
 
Skin Dry, hot
 
Lungs Nl
 
BSs Decr to Absent
 
 
SYMPATHOMIMETIC
 
(Cocaine, amphet, ecstasy, ketamine
 
Temp Nl to Inc (muscle activ inc)
 
RR Inc or Dec
 
HR Inc (Beta 1)
 
BP Inc (alpha 1)
 
LOC Nl, agitated, del or psycho
 
Pupils Mydriatic (alpha 1)
 
Motor Nl to Agitated
 
Skin Sweating
 
Lungs Nl
 
BSs Nl to Dec
 
- usually more tachy and higher BP than anticholinergic and not dry as in anticholinergic.
 
- Dexatrim or Ephedrine - alpha stim, can give phentolamine or Nipride
 
 
SYMPATHOLYTIC (Clonidine)
 
Temp Nl to Dec
 
RR Nl to Dec
 
HR, BP Nl to Dec
 
LOC Nl, Lethargic, or Comatose
 
Pupils Nl to Miotic
 
Motor Nl
 
Skin Dry
 
Lungs Nl
 
BSs Nl to Dec
 
- Consider Sympatholytic when looking at Sedative OD or someone who doesn't respond to Narcan.
 
 
SEDATIVE / HYPNOTIC
 
Temp Nl to Dec
 
RR, HR Nl to Dec All Nl
 
LOC Nl to Leth
 
 
==Source==
 
 
DONALDSON (Adapted from BIRNBAUMER - 7/18/02)
 
 
 
 
[[Category:Tox]]

Latest revision as of 19:18, 20 February 2021

Background

Epidemiology

  • In 2014, ~2.2million human exposures reported to US poison control centers
  • Top 5 substance classes:
    • analgesics (11%)
    • cosmetics/personal care products (8%)
    • household cleaning substances (8%)
    • sedatives/hypnotics/antipsychotics (6%)
    • antidepressants (4%)
  • 1,835 human exposures resulted in death

Autonomic Nervous System Receptors and Their Effects

  • Parasympathetic - ACh is transm
    • Muscarinic
      • receptors in heart, eye, lung, GI, skin and sweat glands
      • Bradycardia
      • Miosis
      • Bronchorrhea / Bronchospasm
      • Hyperperistalsis (SLUDGE)
      • Sweating
      • Vasodilation
    • Nicotinic
  • Sympathetic
    • Alpha effects (vessels, eye, skin)
    • Beta effects (heart, lungs)

Clinical Features

Toxidrome Chart

Finding Cholinergic Anticholinergic Sympathomimetic Sympatholytic^ Sedative/Hypnotic
Example Organophosphates TCAs Cocaine Clonidine ETOH
Temp Nl Nl / ↑ Nl / ↑ Nl / ↓ Nl / ↓
RR Variable Nl / ↓ Variable Nl / ↓ Nl / ↓
HR Variable ↑ ↑ (sig) Nl / ↓ Nl / ↓
BP ↑ ↑ ↑ Nl / ↓ Nl / ↓
LOC Nl / Lethargic Nl, agitated, psychotic, comatose Nl, agitated, psychotic Nl, Lethargic, or Comatose Nl, Lethargic, or Comatose
Pupils Variable Mydriatic Mydriatic Nl / Miotic
Motor Fasciculations, Flacid Paralysis  Nl Nl / Agitated Nl
Skin Sweating (sig) Hot, dry Sweating Dry
Lungs Bronchospasm / rhinorrhea Nl Nl Nl
Bowel Sounds Hyperactive (SLUDGE) ↓ / Absent Nl / ↓ Nl / ↓
^Consider Sympatholytic when looking at Sedative OD or someone who doesn't respond to Narcan
Withdrawal from substances have the opposite effect

Differential Diagnosis for Specific Signs

Hyperthermia

Hypothermia

Increased Respiratory Rate

Respiratory Depression

Bradycardia

PACED

physostigmine

Tachycardia

FAST

Hypotension

CRASH

Hypertension

CT SCAN

Miosis

COPS

Mydriasis

SAW

Coma

LETHARGIC

Seizures

OTIS CAMPBELL

Skin findings

Diaphoresis

SOAP

Dry skin

Bullous lesions/blisters

Flushed/red appearance

Cyanosis

  • Benzocaine and other local anesthetics
  • Cyanokit, nitrites, nitrates, well water (nitrates)
  • Antimalarials
  • Quinolones
  • Dapsone (used to treat leprosy, PCP pneumonia, toxoplasmosis, dermatitis herpetiformis, brown recluse bite)
  • Aniline dyes
  • Phenazopyridine[1]
  • Nitrates, nitrites
  • Ergotamine toxicity|Ergotamine]]

Acneiform rash

Evaluation

Toxicological Exam

  • All vital signs (Temp, RR, HR, BP) + bedside glucose
  • Neurologic exam
    • Level of consciousness
    • Pupillary exam
    • Motor response
    • DTRs
  • Skin Exam - moisture, temp, evidence of injection drug abuse
  • Lung Exam
  • Bowel Sounds
  • ECG (ie. look for QT prolongation, QRS prolongation, etc)
  • Consider CBC, BMP, urinalysis (with ẞ-HCG if appropriate), urine toxicology screen, serum alcohol concentration, VBG
    • The urine screen is a qualitative test -> positivity ≠ acute toxicity
    • It can be falsely positive due to cross-reactivity
    • It can be falsely negative if the substance ingested does not cross-react with the tested analyte
    • The diagnosis of intoxication is clinical!!!

Management

  • Depends on agent
  • See antidotes
  • "Coma cocktail" when suspecting toxic ingestion (mnemonic = "DONT")
    1. Dextrose (50mg IV)
    2. Oxygen
    3. Naloxone (0.2-0.4mg IV/IM, repeat dose 1-2mg)
      • Empiric opioid ingestion treatment
    4. Thiamine (50-100mg)
      • Treat or avoid Wernicke encephalopathy
      • Though some suggest giving thiamine prior to dextrose, do NOT let this delay treatment of hypoglycemia!
      • Case reports of dextrose precipitating Wernicke's involved thiamine-deficient patients receiving prolonged course of IV glucose, NOT with single bolus[2][3]

Disposition

  • Depends on agent

See Also

References

  1. ↑ Jeffery WH, Zelicoff AP, Hardy WR. Acquired methemoglobinemia and hemolytic anemia after usual doses of phenazopyridine. Drug Intell Clin Pharm. 1982 Feb;16(2):157-9.
  2. ↑ Donnino MW, Vega J, Miller J, Walsh M. Myths and misconceptions of Wernicke's encephalopathy: what every emergency physician should know. Ann Emerg Med. 2007;50(6):715-21.
  3. ↑ Gussow, L. Myths of Toxicology: Thiamine Before Dextrose. Emergency medicine news. 2007;29(4):3-11.
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